Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 17/24] xen-blkfront: check for null drvdata in blkback_changed (XenbusStateClosing) | Date | Fri, 6 Nov 2015 11:24:55 -0800 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Cathy Avery <cathy.avery@oracle.com>
commit a54c8f0f2d7df525ff997e2afe71866a1a013064 upstream.
xen-blkfront will crash if the check to talk_to_blkback() in blkback_changed()(XenbusStateInitWait) returns an error. The driver data is freed and info is set to NULL. Later during the close process via talk_to_blkback's call to xenbus_dev_fatal() the null pointer is passed to and dereference in blkfront_closing.
Signed-off-by: Cathy Avery <cathy.avery@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/block/xen-blkfront.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1590,7 +1590,8 @@ static void blkback_changed(struct xenbu break; /* Missed the backend's Closing state -- fallthrough */ case XenbusStateClosing: - blkfront_closing(info); + if (info) + blkfront_closing(info); break; } }
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